Safety-switch



Patented Apr; 26,1921;

2 SHEETS-SHEET I.

H. P. WHIT E, SAFETY'SWITCH.

APPLICATION FILED APR-21. 1920.

.TQEQQ E ATTRND'S l/V VE N TOR H. P. WHITE.

SAFETY SWITCH. APPLICATION FILED APR. 21, 1920.

Patented Apr. 26,1921.

LSHEETS-SHEE? 2.

ATTORNEYS UNITED STATES HERBERT P. WHITE, OF PHILADELPHIA, PENNSYLVANIA.

SAFETY-SWITCH.

Application. filed April 21,

To all whom it may concern:

Be it known that I, HERBERT P. lVHITE, acitizen of the United States, residing in the city and county of Philadelphia, State of Pennsylvania, have invented a new and useful Safety-Switch, of which the following is a specification.

My present invention relates in general to. the class of devices known as safety switches for motor starters ordinarily contained within steel boxings or casings and in which the door of the casing cannot be opened when the switch is closed but only when the switch is opened and the entire moving mechanism dead.

My present invention further embraces certain features of motor-starting construction which may be used in connection with certain elemental devices of a safety-switch which are set forth in an application for patent filed by me upon the 22nd day of December, 1919, as Serial Number 346,601, to which reference may be made.

My present invention has especial relation to a novel and useful mechanism for-controlling the movement of the operating handle which through a drive shaft oper-- ates upon intermediate mechanism which in turn controls the movement of a plurality of swinging contact blades with relation to two corresponding pluralities of fixed con tacts, included in an electric circuit from a source of current to a motor.

My present invention, like my former invention, further includes a novel specific mechanism for controlling the starting and stopping movements and the intermediate dwell of the operating handle to prevent the possibility of the operator from throwin g the switch on the running side of the circuit before first having thrown the switch on the starting side, or source of supply,

and further embraces special contrivances which protect the device as a whole against the possibilitiy of leaving the switch upon the starting side.

Vith the foregoing objects in View, my in vention comprehends certain constructions embodying my invention which are hereinafter particularly explained.

For the purpose of illustrating my inven- Specification of Letters Patent.

Patented. Apr. 26, 1921.

1920. Serial No. 375,512.

tion, I have shown in the accompanying drawings a certain type and embodiment of it which will give in practice satisfactory andreliable results.

It is to be understood, however, that the various instrumentalities which my invention embraces can be variously arranged and organized and that my invention is not, therefore, limited to the precise organization of these instrumentalities as herein'shown and described.

In the drawings,

Figure 1 represents a side elevational view of a side of the casing to which my operating handle is applied,-illustrating in both full and dotted lines different positions of certain of the moving parts.

Fig. 2 represents a longitudinal sectional side elevation on the line 22 of Fig. 1, illustrating a different position of the moving parts represented in Fig. l.

Fig. 3 represents a fragmentary detail of my operating handle and its adjunctive movement-controlling devices.

Fig. at represents a perspective of the dog and pawl which my organization embraces, illustrated as detached from the casing.

Similar numerals of reference indicate corresponding parts.

Referring to the drawings, and to so much of its preferred embodiment as is necessary to an understanding of my improvements,

the box or casing is designated 1, and is preferably of pressed steel and quadrangular and made in the manner usual with casings for this purpose. The door of the casing is designated 2 and is hinged. in the usual way.

Means for effecting the locking of the door under given conditions include a latchcarrying'bar 3 and latches 4- and 5, the bar being mounted upon a driving shaft 6, all as fully set forth in my application for patent referred to, and therefore requiring no further detailed explanation herein.

7 designates an insulating switch-board mounted upon the bottom of the casing, upon which in the usual manner are mounted fuse-supporting clips 8, and live-end switch jaws or contacts 9, and dead-end switch jaws or contacts 10,

In the duplicate arrangement of the contacts, l111 designates fixed spring contacts, which by pairs and upon a side of the casing right-angular to that on which the fixed contacts 9 and 10 are mounted, are alined with said fixed contacts 9 and 10, so that in the swinging of the movable switch blades 12, both sets of fixed contacts, 9-10 and 1111, are in the path of said blades.

The blades are mounted upon an insulating cross bar 13, supported by a carrying bar 14, adapted to be deflected in both directions upon an axis 15 controlled through the driving shaft 6 by the intervention of a driving mutilated gear 16 and an intermeshing driven mutilatedgea-r 17,all as fully set forth in my application for patent.

For present purposes it is sufficient to de scribe the organization by which the operating handle 18 upon the driving shaft 3 is controlled to throw the swinging blade contacts 12 into any one of the three positions illustrated in the several figures of the drawings, namely Figs. 1, 2 and 3.

The means by which I control the movement of this handle is the following To the inner end of the driving shaft 6 the operating handle 18 is locked by a fastening screw 19, so that in the throw of the handle the driving shaft will be given a rotary movement in either the one or the other direction and so as to operate through the intermeshing mutilated gear connection 16 and 17, the swing of the carrying bar 14 and also that of the swinging contact blades 12 and latch carrying bar 3 to lock or unlock the cover 2, all as fully explained in my pending application, to which, as stated, reference is to be made.

20 designates a flat, segmental, carryingplate secured by screws or otherwise to the external face of the wall of the casing through which the driving shaft 6 extends and has its outer hearing.

The carrying-plate 20 is well-made of semi-circular planar form indicated particularly in Fig. 3, so that it has a semi-circular periphery 2 1 which, in the mounting of the plate, extends in a sense diagonally inward from the corner of the sides of the casing upon which are respectively mounted the contacts 9-10 and the contacts 11-11.

Upon its outer face near its lower end, the carrying-plate is provided with a lower stop lug 22, and, similarly, upon its outer face near its upper end it is provided with an upper stop lug 23. This upper stop lug is preferably provided with an adjusting stop screw 25 the terminal end of which itself constitutes the stop device proper of the lug.

The function of these stop-lugs 22 and 23 is to limit the throw in the upper or in the lower direction of the operating handle 18,

because of the encounter with one or the other of said lugs of the abutment lug 26 formed upon and projecting inwardly from the inner side of the operating handle and preferably having a curved inner end, all as shown in the drawings.

27 designate-s a swinging dog, best shown in perspective in Fig. 1, which is a preferably flat plate so connected with the carrying-plate 20 as to have a swinging movement upon a pivot28 extending therefrom.

The dog 27 is flat to the extent of almost its entire length, but near its end farthest from its pivot 28 it is enlarged broadwise to form a stop shoulder 29, the outer surface of which is a continuance of the preferably segmental peripheral curvature of the dog as a whole, but which is extended radially, or broadwise inwardly, so to speak, to form a contact face 30 which equals the breadth of the head portion of the stop shoulder 29 as an entirety, as will be understood from Figs. 3 and at, and which serves in the downward movement of the operating handle 13 to stop said handle through the encounter with it of the abutment 26 of the handle. The under surface of the stop shoulder 29 of the dog is curved as at 37 to form a surface against which the abutment 26 of the handle strikes in the lifting of said handle, as later on explained.

31 designates a pawl pivoted at 32 to the outer face of the dog 27, and formed or provided near its pivot with a pawl-shoulder 33, see Fig. 1, adapted normally to encounter a dog stop 34: attached to or formed upon the outer face of the dog near the pivot 32 of the pawl, which serves to limit the downward movement of the pawl.

designates another, but rearwardly extending, stop, riveted through or otherwise secured to the substance of the dog about intermediate of the dog stop 34 and the contact face 30 of the stop pawl 29 of said dog.

In the mounting of the parts this stop 35, which, as stated, extends rearwardly of the dog, rides upon the segmental periphery 24lof the carrying-plate 20, and, as will be understood, prevents the possibility of the dogs dropping about its pivot 28 out of the normal position with relation to said pivot and said carrying-plate represented in Fig. 3. v

A. reference to Fig. 3 will indicate in full and in dotted lines the two positions of the dog 27 and of the pawl 31.

The dog in full lines is in its normal position and in dotted lines in its abnormal position or that which it is thrown into by the striking action of the abutment 26 on the operating handle against the curved surface 37 when said handle is suddenly lifted from the position shown in Fig. 2 to that shown in Fig. v1.

The movement of the pawl is due to the the result that the handle may pass beyond the pawl until its lug 26 encounters and is finally stopped by. the screw 25 on the side of the carrying plate 20, and in its uppermost position as indicated in Fig. 1.

For clearness of explanation, I have indicated by the numeral 38, a conductor which is a component of the main line circuit which leads from the source of electric supply, and which conductor completes the circuit between the contacts 11-11, when the swinging blades 12 have entered said contacts, and a typical connecting conductor which I have designated 39 from the outer terminals of the conductors 11 to the outer terminals 8 beyond the fuses 41, which through conductors 40 lead to the motor.

When the swinging contact blades 12 are not in contact with either set of the contacts 910 or 1111, but occupy the intermediate position represented in Fig. 3, the current from the source of supply which enters the casing through the conductor 38 will lie dead within the line 45, see Figs. 1 and 3, and not pass on through the contacts 9-10, until the contact blades 12 close the circuit through said contacts 9-10 and through 40 to the motor.

In order to make it impossible to leave the swinging contact blades 12 in closed contact with the contacts 1111, when, for safety, there should be no such closure, I employ a coiled spring which I call an expulsion spring 46, see Figs. 1 and 3, which is secured to a wall of the casing upon which are mounted the contacts 11- 11, and the free end of which spring rests beneath the carrying-bar 14, on an extension or member thereof to which the blades are connected, and so by its expulsive force makes it im possible to close the contacts 1111 in case the operator should remove his hand from the operating lever before throwing said lever over to its vertical position as in Fig. 1, that is to say, throwing it to the running side of the device, and thereby shutting down the motor and making it necessary to repeat the operation.

It is evident that by this spring device, the motor and fuses are protected against closing the switch except by proper and intended method.

Such being a description of a good construction of my present-invention, its operation, in so far as it has not been already explained in connection with the explanations of the elements which compose itand of their movements, will be easily understood to be the following:-

Assuming that a reference to my pending application referred to will make clear the operation of'the latch-carrying bar 3 and.

its latches 4 and 5 which engage with the hasp 4: 1 on the door,an operation dependent upon the rotary movement of the driving shaft 6, the position of the parts illustrated in Fig. 1 is that in which the door is locked andthecurrent from the main line through 38, 11, 12, 11, 39, and 40 flowing to the motor.

It will be apparent that should it be desired to unlock the door for any of the usual purposes, for instance, as replacement of afuse or adjustment of the'contacts, it will be necessary to deflect the operating handle 18' from its upright position into the neutral or mid-way position which said handle is shown in Fig. 3 as occupying and that this movement is of course, accompanied by a movement of the swinging contact blades through their connection with the driving shaft 6, the driving gear 16 and the driven gear 17.

The operation may in another way be de-- scribed as follows In the position of the operating handle represented in full lines in Fig. 3, the current is static.

When, as in Fig. 1, the swinging contact blades 12 have closed the contacts 11"-11', the current will flow through 39 and 40 to the motor; while'when said swinging contact blades are, as indicated in dotted lines in Fig. 3, for the time being, in a position intermediate of the starting terminals 1111 and the running terminals 910,

no current will pass to the motor, but will remain static in the conductor 45.

In this last mentioned, position of the parts, thelatch of the door will be unlocked and no danger will result in a replacement of the fuses or an adjustment of the contacts.-

When, on the other hand, the operating handle 18 is in the dotted line lower posi tion indicated in Fig.3, the latch of the door will be closed and the current from 38 will be flowingthrough 45, fixed contacts 9,'swinging blade contacts 12,fixedcontacts 10',Clips 8,-fuses 4:1,'clips 8, and 40 to the motor.

Assuming the normal position to be that illustrated in Fig. 2 with the handle down in full lines and also in Fig. 3 with the handle down in dotted lines and the door locked, the current, as already explained, will be passing from 38 through the elements above explained to the motor.

When, then, it is desired to throw the handle to efiect the opposite throw of the swinging contact blade, the throw will be a quick one and made in co-action with the swinging dog 27 and its pawl 31, and their adjuncts, as follows Assume thehandle down as in the dotted position of Fig. 3, with its abutment 26 resting on the lower stop lug 22,-in which position the latch to the cover is closed and the current flowing from 38, through &5 and the elements above explained, to the motor, the sudden quick lifting of the handle will first cause its abutment 26 to strike the under curved surface 37 of the stop shoulder 29 of the trigger so as to throw the trigger a up about its pivot 28,-and will then in its further movement and by encountering and passing the toe 36 of the pawl 31, occasion the upward throw of the pawl against its stop 42 and its own contact with and stoppage by the upper stop lug -23,the abutment 26 having completely passed the toe of the pawl thereby permitting said pawl to fall gravitatively about its pivot 32 until its shoulder 33 abuts the dog stop 34t,with

the ultimate result that the handle will stand in its upright position with the door unlocked and the current shunted.

In this upright position of the handle, therefore, the contact through 912 and 10, will have been opened, and, through the mutilated gears 16 and 17 the swinging contact blades will have been thrown against the contacts 1l11 to close the circuit from 38 to said contacts 11-1211 and conductor 39 to permit a flow of the current through a0.

When it is desired again to close the contacts 9 and 10 by throwing the swinging contact blades from their last described and lowest or starting position indicated in dot-' ted lines in Fig. 1, and up into their running positlon by closure of the contacts 9 and 12 as indicated in dotted lines in Fig. 3,-

the handle should be thrown or jerked violently forward and downward, so that in the contact of its abutment 26 with the toe 36 of the pawl 31,-the pawl remaining fixed by the contact of its shoulder 33 with the dog stop 34','-the dog will be thrown with some violence upward against the stop 43.

While the dog is in this position and with its contact face 30 out of the path of the handle abutment 26, the handle can be moved completely down into the position represented in dotted lines in Fig. 3 where it makes contact with the lower stop 22, or,

if desired, can be moved down only so far as to make contact through its abutment 26- with the contact face 30 of the dog, as shown I in full lines in Fig. 3.

Having thus described my invention, I claim 1. A device of the character stated, which comprises in combination :a casing,two

7 are mounted, and which extends exteriorly of the casing,an assemblage of mutilated gears operative upon both the driving shaft and the swinging'contact blades,an operating handle mounted exteriorly of the casing upon the driving shaft,a carrying plate also mounted upon the casing exteriorly of its side which carries the fixed contacts,-a swinging dog provided with a swinging pawl and pivoted to said carrying plate, and an assemblage of stops for the dog,'whereby the dog controls the throw of the handle and through said handle the throw of the swinging contact blades.

2. A safety switch which comprises a casing,a plurality of fixed contacts within and upon one side of the casing,a coun terpart plurality of fixed contacts within said casing upon a side thereof essentially right-angular to the side first mentioned, a plurality of swinging contact blades adapted to close the fixed contacts of either plurality,means for effecting the swinging of said swinging contact blades which comprises a handle having an abutment and operative from the exterior of the casing, a driving shaft, a mutilated gear connection operated through said driving shaft and actuated by said handle,means for control ling thethrow of the handle which comprises a carrying plate affixed to a wall of the casing, a swinging dog pivoted against said carrying plate and provided with a pawl pivoted to it, stops on the carrying plate for controlling the throw of the dog, and stops on the dog for controlling the throw of the .pawl,whereby, under the controlled throw of the handle occasioned by the contact of its abutment with both the dog and its pawl, the throw of the swinging contact blades is effected.

3. In a device of the character described, which embodies in combination, a casing, a dual plurality of fixed contacts oppositely disposed, a plurality of swinging contact blades commontoboth pluralities of fixed contacts,-a driving shaft with reference to which the swinging contact blades are mounted and which extends exteriorly of the casing-an assemblage of mutilated gears operative upon both the driving shaft named plurality of fixed contacts,a swinging dog provided with a swinging pawl and pivoted to said carrying plate, which dog, through an assemblage of stops controls the throw of the handle and through said handle the throw of the swinging contact blades.

4. A safety switch which comprises a casing,a plurality of fixed contacts within and upon one side of the casing,-a counterpart plurality of fixed contacts within said casing upon a side thereof essentially right-angular to the side first mentioned,- a plurality of swinging contact blades adapted to close the fixed contacts of either plurality,means for effecting the swinging of said swinging contact blades, which comprises a handle having an abutment and operative from the exterior of the casing, v

a driving shaft, a mutilated gear connection operated through said driving shaft and actuated by said handle,means for controlling the throw of the handle, which comprises a carrying plate aflixed to a wall of the casing, a swinging dog pivoted against said carrying plate and provided with a pawl pivoted to it, stops on the carrying plate for controlling the throw of the dog, and stops on the dog for controlling the throw of the p'awl,and an expulsion spring within the casing upon which the swinging contact blades when in their starting position are adapted to rest,-whereby, under the controlled throw of the handle occasioned by the contact of its abutment with both the dog and its pawl, as well as by the action of the spring, the throw of the swinging contact blades is effected.

5. In a device of the character stated, in combination with a casing,a carrying plate through which a driving shaft extends and which is provided with an upper handle stop and a lower handle stop,an operating handle exterior of the casing, fixed on the driving shaft,a driving shaft housed in a bearing in the casing and carrying plates,-an operating handle provided with an abutment stop,a swinging dog formed with a stop shoulder having a contact face and with a pawl stop,a pawl pivoted to said dog, formed with a pawl shoulder and controlling the dog with relation to its bearing,-and a stop for the pawl.

6. In a device of the character stated, in combination with a casing which embodies a driving shaft extending exteriorly of it, a dual plurality of fixed contacts, a plurality of swinging contact blades common to both pluralities of fixed contacts and adapted in the movement of the shaft to be swung in either direction,-a carrying plate through which the driving shaft extends,a handle having an abutment and fixedly mounted on the shaft exteriorly of the carrying plate,a swinging dog pivoted at its upper end exteriorly of the carrying plate,at its lower end having a stop shoulder and a contact face, and intermediately of its length having a pawl stop,a pawl pivoted to and extending below the lower part of said dog and having a shoulder adapted to contact with the pawl stop,an upper handle stop on the carrying plate,and a lower handle stop on the carrying plate.

HERBERT P. WHITE, Witnesses GEORGE W. WATSON, FREno J. GAY. 

